The present invention relates to an rpm regulator for fuel injection pumps used in internal combustion engines and more particularly to an rpm regulator for fuel injection pumps including an intermediate lever, an rpm governor, a main control spring, a second spring, and a stop. One end of the intermediate lever engages the fuel quantity setting member of the injection pump and is itself engaged by the rpm governor which acts with an rpm dependent force in opposition to an arbitrarily changeable force of the main control spring and also in opposition to the force of the second spring disposed in series with the first spring and deformable up to the stop.
A known serial injection pump of this type includes a centrifugal governor which operates in opposition to a main control spring. The main control spring, whose preload is changeable, sets a control rod. The centrifugal governor has a displaceable sleeve, the displacement of which is transmitted directly to the control lever; and, on the other hand, by a second lever rigidly connected to the first lever to a leaf spring consisting of several individual leaves.
The two ends of the leaf spring are held by an angled lever engaged by the main control spring and may be deformed on the angled lever up to an adjustable stop. Thus the leaf spring acts together with the main control spring to oppose the setting motion of the centrifugal governor so that, at the outset, the increasing governor setting forces lead to the deformation of the leaf spring up to its stop and only thereafter to a deformation of the main control spring. Hence, by means of this leaf spring, which in normal operation always engages its stop, one may obtain a starting excess fuel quantity which is automatically shut off after engine starts. In these installations, the control lever and the angled lever each have a separate pivotal axis.
One disadvantage of the apparatus described above is that it is expensive, especially in view of the method of fastening and the design of the leaf spring and its adjustment. Another disadvantage is that the control lever and the angled lever each have a separate axis which makes the apparatus not only expensive, but also wasteful of space. Still another disadvantage resides in the fact that the separate disposition of the levers requires large lever motions which require the centrifugal force governor to have a large working capacity.